Drying roll



Jan. 27, 1959 v 's c. NELSON ETAL' 2,870,546

DRYING ROLL Filed Aug. 30; 1954 United States DRYING ROLL Application August 30, 1954-, Serial No. 453,tl62

1-2 Claims. (Cl. 34-124) The present invention relates to a drying roll which may be used for drying continuously traveling sheets of material such as cellophane. In particular, the, invention relates to a drying roll which when heated to drying temperature maintains a temperature ditferential between the end and central surface portions of the roll. In addition, the temperature differential may be adjusted as desired.

In the production of continuous paper sheets, such as cellophane, it is the general practice to dry the wet sheets by passing them over a series of rotating, hollow rolls having smooth uninterrupted surfaces and which are internally heated by hot water or'steam. The surfaces of these rolls are of uniform temperature and when they are used to dry continuous cellophane sheets many difiiculties and disadvantages are present which tend to produce products of inferior quality.

When drying cellophane with the uniform surface temperature rolls, it has been found that the film edge portions are dried more rapidly than the central portion of the film. As a result of such drying pattern, the edge portions of the film shrink morerapidly than, the central portion of the film during normal transverse shrinkage. As a result, there occurs abnormal shrinkage adjacent the edge portions of the film whereby the finished film or sheet has curly or floppy edges and an uneven distribution of moisture across the film.

With such non-uniform drying, a strain is producedin the final film whereby the filmis neither flat nor straight. A film which is not straight is one which will not lie substantially-in a straight'line when laid on a table. A crosssection of' a length of cellophane film which is. not fiat, if stretched between two end supports, shows a curved line instead of astraight line when laid on a table. A cross section of a length of cellophane film which is not flat ifj stretched between two. end supports, shows a curvedline instead of a straight horizontal line. Obvious ,diliiculties areencountered when using such a strained film in wrapping machines, bag making mae nd niu tieln printi machines.

Various dryingrnethpds. and apparatus. have been developed in anattempt. to overcome the difficulties and disadvantages, mentioned above, but without much success. For example clients; have been. made to mechania lypreve tthe sh i kage Q he fi m dur ng dry operation by clamping; the film; at: both, edges to prevent itfron shrinking transversely of its direction of travel. HQWQver, it has been found that such a drying system causestears or weak spotsadjacent the edge portions of the sheet on film.

It is an object of the. present invention to provide a rotatable drying roll which-will uniformly dry a con tinuoussheet traveling thereover to produce a fiat and straight result-ant sheet. I

It is; also anobject ofthe present invention to provide a rotatable drying roll wherein a temperature differatent 2, ential is maintained between the end and central portions of the roll surface.

It is a further object ofthe invention to provide a drying roll wherein the temperature, differential of the roll may be adjusted as desired.

A more complete understanding of the invention may be had from a study of the descriptionv and the drawings wherein:

Figure 1 is an elevation, partially in section, of the drying roll.

Figure 2 is an enlarged view in section of a portion of one end of the roll of Figure 1.

Figure 3 is a sectional detail of another embodiment of the invention.

Figure 4 is a sectional detail of a further embodiment I tions for moving them back and forth within the drurn,v

and a heating medium circulating system is provided for introducing and exhausting a suitable drum heating medi um to andfromthe area between the partitions.

Referring now to Figure 1 of the drawing, the drying roll assembly comprises a drum section 1 having end. supports 2 and 3 secured to the drum ends by bolts. 4, 4

or other suitable securing means. The rotatable drying roll 1 is journaled in a suitable frame work (not shown) by positioning the drum end supports 2 and 3, within. suitable framework bearings (not shown).

As seen in Figures 1 and 5, one of the adjustable partitions 15, is positioned within the drum 1 near one end thereof hereafter termed the service end. The service end partition includes a threaded hub 16. and awebv section 17 which is expanded; at its periphery to form a rim 18, the outer surface of which is grooved to accommodate a resilient tubular sealing ring 19 cemented or otherwise secured therein. The ring 19 seals ofi the space between the partition 15' and the service end of. the drum from the remainder of the drum to prevent the heating medium from entering into the sealed off area.

The sealing ring 19 has a diameter which is greater than the distance between the inner drum surface and.

the flange 18 so that the sealing ring is compressed to provide an adequate seal. formed of a natural or a synthetic rubber such as Neoprene (registered trademark). For adjusting the position of the partition 15 within the drum 1, adjusting rod 20 is positioned within and extends from beyond the end support 3 into the drum interior and is screwed into the threaded hub 16 A. ball grip 21 is afiixed to the free end of the rod 20. for moving the partition 15 back and forth within the drum 1. Any suitable means such as a set screw 22 holds the rod and partition in place after the partition has been properly positioned Within the drum 1. In the alternative, the rod 20 may be unscrewed from the disc- 15 after the disc is properly positioned within the drum 1 and a plug placed within the end support 3 to close-ofi; the drum-interior from the atmosphere.

A second adjustable partition 24 (Figure 2) is positioned within the opposite portion or drive. end of the drum. The partition 24 includes hub 25, a web section 26 which is expanded at itsperiphery to form a 2,7, the outer surfacev of which is, grooved to accommodate a second resilient ring 19- compressed between the rim 27 and. the inner surface of the drum 1. Sleeve 29, screwed into, the hub 25 of partition 24, is connected by Thesealing ring 19 may be or reducing coupling 30 with sleeve 31 of smaller diameter which extends through and beyond end support 2 (Figure 1). A hand grip 32 is affixed to the periphery of sleeve 31 so that the connected sleeves 31 and 29 and partition 2.4 may be moved toward or away from the partition 15 to increase or decrease the area between the partitions. Partition stop 33 (see Figure 2) limits the movement of adjustable partition 24 toward the end of the drum 1. A similar stop is also used to limit the move ment of partition 15 with respect to end support 3. When the adjustable partition 24 is positioned as desired, set screw 34 extending through end support 2 may be tightened to hold the sleeve 1 and partition 24 in position.

For supplying a heating medium such as steam or hot water to the area between the partitions a fixed feed pipe 35 extends from a point beyond the end of sleeve through coupled sleeves 31 and 29, and into the area tween the two partitions 15 and 24 (Figures 1 and 2). The heating medium introduced through pipe 35 is circulated within the area and exhausted therefrom through a path defined by the bores of sleeves 29 and 31 and periphery of feed pipe 35. The sealing rings 19 prevent the heating medium from passing into the areas between the partitions and the end supports. The exhaust medium passes outwardly into the atmosphere or it may be collected as it passes beyond the end of sleeve 31 and passed to a conditioning device which will prepare the exhausted medium for use in the drum.

Figure 3 shows an embodiment ofthe invention for sealing oh the area between the adjustable partitions and the drum ends wherein a sponge rubber strip 40 is cemented around and to the inner surface of drum l. The thickness of strip iii is greater than the distance between the peripheral flange 41 of the adjustable partition 42 and the inner surface of drum It so that the strip is compressed to provide an effective seal. The strip as is of sufiicient length to accommodate any position of partition Figure 4 shows another embodiment of the invention for sealing off the area between the adjustable partitions and the drum ends wherein a sponge rubber ring 45 is clamped to the partition 46 being held in position by retaining ring 47 and bolt 48 or another suitable securing means.

From the above description, it is apparent that the portions of the roll surface near the ends of the roll will be maintained at lower temperatures than the central portions of the roll regardless of the area between the two partitions. This temperature differential is, of course. achieved because of the natural resistance of the metal from which the roll is constructed to heat conduction. The temperature will gradually decrease as the heat from the central heated surface portion is conducted from the center of the roll surface toward the surface ends thereof. When the partitions are close together, the heating medium is confined to a small central portion of the roll and the central surface portion of the roll will be maintained at a high temperature while the end surface portions will be maintained at a lower temperature than the central surface portion. When the partitions are spaced far apart, the central surface portion of the roll will then be maintained at a low temperature and the end surface portions of the roll Will be maintained at. still slightly lower temperature than the central surface portion.

In practice, an experimental drying run is conducted during which the partitions are constantly adjusted While the rolls are rotating until the optimum temperature differential for the roll for uniform sheet drying is achieved. The frictional contact between the resilient rings 19 and the inner drum surface is sufiicient to hold the partitions in place, however if required, the set screws 22 and 34, or other suitable securing means, may be used to hold the partitions in place. After proper positioning of the partitions, the roll is ready for production usage and no further adjustment of the partitions is made dur" ing the production run since any change in temperature differential during operation results in non-uniformity with respect to shrinkage within the sheet.

it is to be understood that changes and variations may be made without departing from the spirit and the scope of the invention as defined in the appended claims.

We claim:

1. A drying roll for drying a continuous sheet of fiexible material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, means for supplying a heating medium to the interior of the drum, and at least one unbroken partition mounted within and closing off one portion of the drum interior from the remaining portion of the drum interior for effecting a temperature differential between the two portions of the drum interior and the corresponding portions of the drum surface.

2.. A drying roll for drying a continuous sheet of flex ihle material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, at least one adjustable partition within the drum which is rotatable therewith for sealing off a section of the drum interior, means connected with the partition for adjusting and controlling the position of the partition within the drum interior, and means for introducing a drum heating medium into the drum interior at a point beyond the sealed-01f section of the drum interior.

3. A drying roll for drying a continuous sheet of flexible material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, end supports for the drum, at least one adjustable partition within the drum which is rotatable therewith for sealing off a section of the drum interior, means connected with the partition and extending externally of the drum through one of the end supports for adjusting and controlling the position of the partition within the drum interior, and means for introducing a drum heating medium into the drum interior at a point beyond the sealed off section of the drum interior.

4. A drying roll for drying a continuous sheet of flexible material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, end supports for the drum, a first adjustable partition within the drum which is rotatable therewith for sealing off a section of the drum interior, a second adjustable partition within the drum which is rotatable therewith for sealing ofl? a second section of the drum interior, means connected with one of the partitions and extending externally of the drum through one of the end supports for adjusting and controlling the position of the partition within the drum interior, and means for introducing a drum heating medium within the area between the two partitions.

S. A drying roll for a continuous sheet of flexible material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, hollow end supports afiixed to the drum ends, a first adjustable partition within the drum which is rotatable therewith for sealing off a section of the drum interior, a second adjustable partition within the drum which is rotatable therewith for sealing off a second section of the drum interior, means connected with the first adjustable partition and extending through one drum end support for adjusting and controlling the position of the adjustable partition within the drum interior, means connected with the second adjustable partition and extending through the opposite end support for adjusting and controlling the position of the second adjustable partition within the drum interior, and means through which a drum heating medium is introduced within the area between the two partitions.

6. A drying roll for drying a continuous flexible material sheet according to claim 5 wherein the first adjustable partition comprises a hub, a web section, a rim formed by expansion of the web section, a sealing ring of resilient material positioned around the rim, and a rod secured to the hub for moving the partition back and forth within the drum.

7. A drying roll for drying a continuously traveling sheet of flexible material according to claim 6 wherein the resilient sealing member comprises a tubular ring.

8. A drying roll for drying a continuously traveling sheet of flexible material according to claim 5 wherein the second adjustable partition comprises a hub, a web section, a rim formed by expansion of the web section, a sealing ring of resilient material positioned around the rim, a sleeve assembly secured to the rim, which sleeve assembly extends through and beyond the opposite end support, and a hand grip affixed to the free end of the sleeve for moving the partition back and forth within the drum.

9. A drying roll for drying a continuously traveling sheet of flexible material according to claim 8 wherein the resilient sealing member comprises a tubular ring.

10. A drying roll for drying a continuously traveling sheet of flexible material comprising a drum, hollow end supports for the drum, an adjustable partition within the drum which is rotatable therewith for sealing off a section of the drum interior, a sealing strip of resilient material adhered to the inner surface of the drum which cooperates with the adjustable partition to seal off the space between the drum end and the adjustable partition, means for moving the adjustable partition back and forth within the drum interior, and means through which a heating medium is introduced within the drum interior at a point beyond the sealed off section of the drum interior.

11. A drying roll for drying a continuously traveling sheet of flexible material comprising a rotatable hollow drum having a substantially smooth and uninterrupted surface over and against which the sheet travels, hollow end supports for the drum, an adjustable partition Within the drum which is rotatable therewith for sealing ofl a section of the drum interior, a resilient sponge rubber ring positioned around the adjustable partition, means for retaining the sponge strip in position on the partition, means for adjusting and controlling the position of the partition within the drum interior and means through which a heating medium is introduced within the drum interior at a point beyond the sealed off section of the drum interior.

12. A drying roll for drying a continuously traveling sheet of flexible material comprising a drum, hollow end supports for the drum, a first adjustable partition within the drum, a second adjustable partition within the drum, a sleeve assembly secured to the second adjustable partition, said sleeve assembly extending through an end support to a point beyond the end support, a hand grip aflixed to the free end of the sleeve assembly, a pipe extending through the sleeve assembly to a point beyond the adjustable partition for supplying a heating medium between the partitions, and a heating medium exhaust channel defined by the bore of the sleeve assembly and the periphery of the feed pipe.

References Cited in the file of this patent UNITED STATES PATENTS Germany Dec. 18, 1952 

